Improve build times by caching cargo install artifacts for diesel, clippy, and rustfmt

The primary change is to set `CARGO_TARGET_DIR=target` which instructs
`cargo install` to use the target/ directory which is cached between
builds on travis.  This is only available on recent nightlies so I've
bumped clippy and rustfmt versions.

Unfortunately, `ring v0.11.0` does not compile on recent nightlies and
upstream provides no support for older versions.  Therefore I've added
a patch section to use a git repo that incorporates the fix and a few
other cleanups.  This issue would have broken the build soon anyway
when rust 1.24 goes into beta.

A few other changes:

* only `npm install` on the stable job
* removed travis-cargo which appears to be unused
* removed rustfmt configuration options that were removed upstream

Author: jtgeibel

.rustfmt.toml

@@ -1,11 +1,4 @@
-fn_args_layout = "Block"
-array_layout = "Block"
-control_style = "Rfc"
-where_style = "Rfc"
-generics_indent = "Block"
-fn_call_style = "Block"
 combine_control_expr = true
-fn_args_paren_newline = false
 max_width = 100
 error_on_line_overflow = false
 write_mode = "Overwrite"

.travis.yml

@@ -21,9 +21,7 @@ before_install:
   - nvm install 8
 
 install:
-  - pip install 'travis-cargo<0.2' --user && export PATH=$HOME/.local/bin:$PATH
-  - npm install
-  - cargo install --force diesel_cli --vers 0.16.0 --debug --no-default-features --features postgres && export PATH=$HOME/.cargo/bin:$PATH
+  - cargo install --force diesel_cli --vers 1.0.0-rc1 --debug --no-default-features --features postgres && export PATH=$HOME/.cargo/bin:$PATH
 
 before_script:
   - diesel database setup
@@ -44,16 +42,17 @@ matrix:
   allow_failures:
     - rust: nightly
   include:
-  - rust: nightly-2017-11-07
+  - rust: nightly-2017-12-28
     script:
-    - cargo install --force rustfmt-nightly --vers 0.2.15
-    - cargo install --force clippy --vers 0.0.169
+    - cargo install --force rustfmt-nightly --vers 0.3.4
     - cargo fmt -- --write-mode=diff
+    - cargo install --force clippy --vers 0.0.177
     - cargo clippy
   - rust: stable
     script:
     - cargo build
     - cargo test
+    - npm install
     - npm test
   - rust: beta
     script:
@@ -68,6 +67,7 @@ env:
   global:
     - DATABASE_URL=postgres://postgres:@localhost/cargo_registry_test
     - TEST_DATABASE_URL=postgres://postgres:@localhost/cargo_registry_test
+    - CARGO_TARGET_DIR=target
 
 notifications:
   email:

Cargo.lock

@@ -84,3 +84,7 @@ tokio-service = "0.1"
 dotenv = "0.10"
 diesel = { version = "1.0.0-beta1", features = ["postgres"] }
 diesel_migrations = { version = "1.0.0-beta1", features = ["postgres"] }
+
+# Remove once cookie depends on ring >= 0.13.0
+[patch.crates-io]
+ring = { git = "https://github.com/SergioBenitez/ring", branch = "v0.11" }